Preterm birth can result in problems of the lungs, heart, brain, and other body systems of a newborn baby. Recent advances in the study of preterm labor have identified effective drugs that may delay delivery. The longer the baby can develop in the womb, the less likely he or she will have problems associated with preterm birth.
If you are having signs of premature labor, call a doctor immediately. Symptoms of preterm labor include (Mayo Clinic, 2012):
- Frequent or consistent contractions (tightening in the belly)
- Low back pain that is dull and constant
- Pressure in the pelvis or lower abdominal area
- Mild cramps in the abdomen
- Water breaking (watery vaginal discharge in a trickle or a gush)
- A change in vaginal discharge
- Spotting or bleeding from the vagina
If you are less than 37 weeks pregnant when you experience these symptoms, your doctor may try to prevent delivery by offering certain medications. In addition to giving tocolytic medicines (which prevent contractions) for preterm labor, your doctor may prescribe steroids to improve the baby's lung function. If your bag of water has broken, you may also be given antibiotics to prevent infection and help you stay pregnant longer.
Some women go into labor very early. If you deliver before 34 weeks, receiving corticosteroid injections can greatly improve your baby's chances of doing well (Lefevre, 1992). This discovery is one of the most important recent advances in caring for pregnant women at risk of preterm delivery.
Steroids are usually injected into one of the mother's large muscles (arms, legs, or buttocks). The injections are given two to four times over a two-day period, depending on which steroid is used. The most common steroid, betamethasone (Celestone), is given in two doses, 12 mg each, 12 or 24 hours apart. The medications are most effective from two to seven days after the first dose. Corticosteroids are not the same as the bodybuilding steroids used by athletes. Multiple studies have shown that prenatal corticosteroids are very safe for mothers and babies (Roberts and Dalziel, 2010).
What Are the Benefits of Steroids?
Steroid treatment reduces the risk of lung problems for babies who are born early, particularly for those born between 29 and 34 weeks of pregnancy (NIH, 1994). Babies born more than 48 hours, but less than seven days from the first dose of steroids, show the greatest benefit (McEvoy, et al., 2000). The steroid treatment cuts the risk of lung disease in half and reduces a premature baby's risk of dying by up to 40 percent (Carlo, et al., 2011; Meneguel, et al., 2003). All babies born at less than 28 weeks had lung problems, but the problems were milder for those who got steroids before birth. Steroids may also help reduce other complications in the baby (Roberts & Dalziel, 2008). Studies have shown that some babies have fewer problems with their intestines and with bleeding in the brain when their mothers received a course of betamethasone prior to birth.
If you are admitted to the hospital in preterm labor, or if you have a medical problem that your doctors worry will require an early delivery, you will probably be offered a course of steroids. Staying pregnant for those first two days after a corticosteroid shot is the first major milestone for you and your baby (or babies).
What Are the Risks of Taking Steroids?
Studies in animals have shown that giving steroids to a pregnant female can affect the immune system, neurological development, and growth of her offspring. However, these effects have shown up only in studies where steroids were given in very high doses or early in the pregnancy. In the treatment of preterm labor, steroids are given later in pregnancy.
Human studies have not shown any significant risks associated with a single course of steroids. One study followed infants whose mothers were given steroids during pregnancy until the children were twelve years old . These studies showed no adverse effects from the steroids on the child's physical growth or development. Still, more studies need to be done.
In the past, women at risk for preterm delivery received steroids once a week until they delivered. Data from infants and animal studies showed that multiple courses of steroids were linked to babies with lower birth weights and smaller heads (Murphy, et al., 2012). Currently, repeat doses are not recommended, unless you are participating in a research study.
Who Should Take Steroids?
In 1994, the National Institutes of Health (NIH) published guidelines on the administration of steroids to women with preterm labor (NIH, 1994). According to these guidelines, doctors should consider giving steroids to all women who:
- are at risk for preterm delivery between 24 and 34 weeks of pregnancy
- receive medications to help stop labor (tocolytic medications)
Who Should Not Take Steroids?
Steroids may make diabetes (both long-standing and pregnancy-related) more difficult to control. When given in combination with a beta-mimetic drug (terbutaline), they can be even more problematic. Women with diabetes will require careful blood sugar monitoring for three to four days after receiving steroids. In addition, women with active or suspected infection in the womb (chorioamnionitis) should not receive steroids.
Progestin Hormones: 17-OHP
Some women are more likely than others to go into labor early. Women at high risk of a preterm delivery include women who (Mayo Clinic, 2011):
- have already given birth to a preterm baby
- are carrying more than one baby (twins, triplets, etc.)
- got pregnant shortly after a previous pregnancy
- use tobacco, alcohol, or illicit drugs
- conceived through in vitro fertilization
- have had more than one miscarriage or abortion
- have other health problems (such as an infection, weight concerns, anatomical abnormalities in the uterus or cervix, or certain chronic conditions)
- suffer from poor nutrition
- experience a very stressful or traumatic event during pregnancy (physical or emotional)
- are African American
Despite these known risks, many women who experience symptoms of preterm labor have no clear risk factors.
If you have had a preterm birth in the past, your obstetrician may recommend you get a progesterone shot or pessary. The most common form of progesterone hormone administered to prevent preterm birth is the 17-OHP shot, or 17-alphahydroxyprogesterone caproate. This shot is currently very affordable—about $15 each—compared to the costs associated with a preterm birth.
The 17-OHP shot is a synthetic progestin that is often administered prior to the 21st week of gestation. It is intended to prolong pregnancy. The hormone works by keeping the uterus from contracting. The shot is typically given into the muscles of the woman on a weekly basis. If it is given as a pessary, it may be inserted into the vagina. A prescription is required for this hormone treatment, and both the shots and the suppositories should be administered by a physician.
What are the Benefits of Progesterone Shots?
A review of clinical studies of 17-OHP has demonstrated its ability to prolong pregnancy (Dodd, Flenady, Cincotta, & Crowther, 2012). Women who are at risk of delivering a baby before 37 weeks may be able to stay pregnant longer if they receive 17-OHP prior to the completion of 21 weeks of pregnancy. Other studies have demonstrated that if preterm birth does occur, babies who survive have fewer complications if their mothers received 17-OHP before the birth (Meis, et al., 2003).
What are the Risks of Progesterone Shots?
As with any shot and hormone administration, 17-OHP shots may cause some side effects. The most common include pain or swelling in the skin at the injection site, a skin reaction at the injection site, nausea, and vomiting (How & Sibai, 2009). Some other women experience side effects such as mood swings, headaches, abdominal pain or bloating, diarrhea or constipation, changes in sexual drive or comfort, dizziness, allergy, or flu-like symptoms, among others (How & Sibai, 2009). Women who receive the shots are more likely to have skin problems at the injection site, and women who receive the vaginal suppository are more likely to have unpleasant discharge or irritation in the vagina.
There is no indication that 17-OHP shots have any negative effect on miscarriage, stillbirth, preterm birth, or birth defect risk. There is not enough known about the long-term effects on mothers or babies to recommend shots for women with other predisposing factors for preterm birth. Although 17-OHP shots may reduce the risk of preterm birth and some of its complications, it does not appear to reduce the risk of infant death.
Who Should Get 17-OHP Shots?
Women who have previously experienced preterm labor are often offered a hormone shot called 17-OHP. The American College of Obstetricians and Gynecologists (ACOG) recommends that only women with a history of labor prior to 37 weeks gestation receive a 17-OHP shot (ACOG, 2003). This is because there is not enough research on the drug’s best dose and delivery options (and long-term effects) for it to be used regularly in women with less obvious risk factors.
Who Should Not Get 17-OHP Shots?
Women without a prior preterm birth should not receive 17-OHP shots until more research confirms their safety and effectiveness for other risk factors. In addition, women with allergies or serious reactions to the shot may wish to discontinue their use.
In addition, there are some situations in which a longer pregnancy may be harmful to the mother or the fetus. Preeclampsia, amnionitis, and lethal fetal anomalies (or imminent fetal death) may make a prolonged pregnancy dangerous or fruitless. Always consult carefully with a health professional before deciding to receive or refuse 17-OHP shots or suppositories.
Tocolytic medications are used to delay delivery. A variety of drugs have similar effects for delaying delivery 48 hours or more when a woman is experiencing preterm labor. Tocolytic drugs include the following medications (ACOG, 2003):
- terbutaline (this drug is no longer considered safe for injection)
- magnesium sulfate
- calcium channel blockers
Tocolytics are prescription drugs that should only be administered between weeks 20 and 37 of pregnancy if symptoms of preterm labor exist. They should not be combined except under the close supervision of a physician; combining tocolytics can cause problems for both the mother and the baby (ACOG, 2003). In general, tocolytic drugs only delay delivery. They do not prevent complications of preterm birth, fetal death, or maternal problems associated with preterm labor. They are often given with prenatal corticosteroids.
What are the Benefits of Tocolytics?
All tocolytics, but prostaglandin inhibitors in particular, are effective at delaying delivery between 48 hours and 7 days (Haas, et al., 2009). This is done to allow corticosteroids time to speed fetal development. Tocolytics themselves do not decrease the chances of death or illness for the newborn; instead, they merely give extra time for the baby to develop or for other drugs to work. Tocolytics may also delay delivery long enough for a woman to be transported to a facility with a neonatal intensive care unit if preterm birth or complications are likely.
What are the Risks of Tocolytics?
Tocolytics have a variety of side effects that range from very mild to very serious. Common side effects include dizziness, headaches, lethargy, flushing, nausea, and weakness. More serious side effects can include heart rhythm problems, blood sugar changes, breathing difficulties, and changes in blood pressure (ACOG, 2003). Because certain tocolytic drugs carry different risks, the specific drug chosen should depend on the woman’s health and personal risks. There is some controversy over whether tocolytics themselves can cause problems at birth, such as breathing problems for the baby or infection in the mother (Mackeen, Seibel-Seamon, Grimes-Dennis, Baxter, & Berghella, 2011).
Who Should Get Tocolytics?
Women experiencing the symptoms of preterm labor, particularly before 32 weeks gestation, should receive tocolytic drugs (Haas, et al., 2009).
Who Should Not Get Tocolytics?
According to ACOG, women should not get tocolytic drugs if they have any of the following contraindications (ACOG, 2003):
- severe preeclampsia
- placental abruption
- infection of the uterus
- lethal fetal abnormalities
- signs of imminent fetal demise or delivery
In addition, each type of tocolytic drug has risks for women with certain conditions. For example, women with diabetes or thyroid problems should not receive ritodrine, and women with serious liver or kidney problems should not receive prostaglandin synthetase inhibitors (ACOG, 2003). A physician should have a thorough understanding of the woman’s particular health problems before prescribing a specific tocolytic drug.
Antibiotics are routinely given to women in preterm labor when the bag of water surrounding the fetus has broken. This is because ruptured membranes put a woman and her baby at greater risk for infection. In addition, antibiotics are frequently used to treat infections such as chorioamnionitis and Group B streptococcus during preterm labor. Antibiotics require a prescription and are available in pill form or intravenously.
What are the Benefits of Antibiotics?
Many large, well-designed studies have shown that antibiotics reduce risks to mothers and babies and prolong pregnancy after a woman's water breaks early (Kenyon, Boulvain, & Neilson, 2010). Some studies have shown that antibiotics may prolong pregnancy and reduce problems in the newborn (Mercer, et al., 1997). It is possible that antibiotics may delay or prevent preterm birth by treating conditions (such as infections) that can cause preterm birth. On the other hand, it's unclear whether antibiotics can delay delivery for women who are in preterm labor but have not broken their water. Reviews combining multiple studies have failed to show a significant advantage to using antibiotics for preterm labor in women who have an intact bag of water (King, Flenady, & Murray, 2011). For now, using antibiotics to help treat all preterm labor remains controversial.
There is also data showing that antibiotics are helpful during preterm labor for women who carry bacteria called group B streptococcus (GBS). About one in five women will carry GBS, and babies who get infected during labor and delivery can become very sick. Antibiotics can treat GBS and reduce complications of a subsequent infection in the newborn, but carry risks for the mother (Ohlssen & Shah, 2009). Most care providers test women for the bacteria about a month before their due date. The test involves taking swab samples from the lower vagina and rectum. Because it can take two or three days for test results to be returned, the general practice is to go ahead and begin treating a woman for GBS before confirmation of infection if a woman is in preterm labor. Most doctors think that this presumptive treatment is justified because as many as one in four women test positive for GBS. Ampicillin and penicillin are the antibiotics most commonly used for treatment.
What are the Risks of Antibiotics?
The primary risk of antibiotics during preterm labor is an allergic reaction from the mother. In addition, some babies may be born with an infection that has resistance to antibiotics, making treatment of post-partum infections in the baby more difficult (Edwards, Clark, Sistrom, & Duff, 2002).
Who Should Get Antibiotics?
According to ACOG, only women with signs of infection or a ruptured membrane (early water break) should receive antibiotics during premature labor (ACOG, 2009). It is not currently recommended for routine use in women without either of these problems.
Who Should Not Get Antibiotics?
Women without signs of infection and with intact membranes should likely not receive antibiotics during preterm labor (ACOG, 2009). In addition, some women may have allergic reactions to particular antibiotics. Women with known allergies to antibiotics should receive alternative antibiotics or none at all, following the recommendations of health professionals familiar with the mother’s risks (Sayres, 2010).